If a GPRS call (ATD*99***1#) is made and then subsequently disconnected (by giving ATH), the “NO CARRIER” response take a long time to come. Is there a way to reduce this time?

Following ways can be used to reduce the time for receiving a "NO CARRIER" response after terminating the GPRS call:
– The DTR pin can be changed to logical low. This can be done using the external application or by using a GPIO (connected to DTR pin) to change the logic level of DTR pin.
– The CMUX protocol can be enabled and a "STATUS" packet to indicate the lowering of DTR signal can be sent to the module. This will close the GPRS session immediately. This method can be used if the external application does not have the DTR signal.